The shop is based in Claudio Coello St, Madrid at walking distance from Carmina shop. I've read that prices for box calf are EUR 140 and cordovan EUR 290. This is their tumblr meermin.tumblr.com, can anyone care to comment about their quality?

On the other hand last week I was visiting my parents place in the north of Spain and their local shoe shop had some Carmina's on display at EUR 290 for box calf and EUR 475 for cordovan..... I asked my parents to pick for some double monk at the Xmas where they will be at a 15% off

Just reading the link establishes that it another arm of the family business that has been flogging shoes to high end Japanese boutiques/shops for years and now the company is moving to bricks and mortar stores in Madrid Bilbao and Tokyo selling lower end shoes leaving Carmina to the top end. It explains that another brother established Yanko shoes and sells a million pairs a year.

I just read on an Spanish forum that Meermin and Carmina used to buy together batches of leather from the same place. Also it seems that Carmina outlet in Granada used to sell Meermin shoes a few years back.

Right, just got back from Madrid.
Meermin was amazing.
They had a back room dedicated to their hand welted shoes.
I checked to be double sure and was told that the regular shoes are machine welted and the Linea Meastro are welted by hand.

Their Cordovan shoes had a last that I just couldn´t get to fit my feet, I would also say that the finishing is noticeably worse than Carmina.
To be honest this is not a huge problem on some Cordovan shoes but it made the Oxford laced ones look a little sloppy.
The tassel loafers were finished to a higher standard though.

The shop was incredibly busy despite only being open for 2 months.
Around 25 people came in during the hour or so I spent there.